The present invention relates to a compressor having a structure for suppressing pulsation.
A typical compressor includes a rotatable shaft, piston s housed in cylinder bores, a suction chamber and discharge chamber. As each piston is reciprocated in the corresponding cylinder bore by rotation of the rotatable shaft, gas is drawn into the cylinder bore from the suction chamber, which is defined in a rear housing member. The gas is then compressed by the piston and discharged to the discharge chamber, which is defined in the rear housing member.
The discharge chamber suppresses pulsation of discharged gas, and the suction chamber suppresses pulsation of drawn gas. The greater the volume of the discharge chamber is , the more effectively the discharge pulsation suppression is. Also, the greater the volume of the suction chamber is, the more effective the suction pulsation suppression is.
Japanese Unexamined Patent Publication No. 11-125178discloses a compressor that suppresses discharge pulsation. The compressor of the publication has a bracket protruding from a rear housing member. The outer wall of the rear housing member bulges by the same amount as the bracket. The bulge is hollow, and the interior of tho bulge forms part of a discharge chamber. This structure e increases the volume of the discharge chamber, which improves the pulsation suppression without increasing the axial dimension of the compressor.
However, such expansion of the discharge chamber expands the total area of the walls defining the discharge chamber, which increases the weight of the compressor. Although the axial dimension of the compressor is not increased, the volume of the compressor increased. As a result, the compressor is more likely to interfere with other devices. The increased weight and size are disadvantageous when installing the compressor in a vehicle.
Accordingly, it is an objective of the present invention to provide a compressor that effectively suppresses pressure pulsation without increasing the weight of the compressor or the volume of any part that might cause interference during installation.
In accordance with the present invention, there is provided a compressor comprising a housing having a suction chamber and a discharge chamber defined therein. Gas is drawn from the suction chamber into cylinder bores and discharged from the cylinder bores into the discharge chamber by the reciprocating movement of a plurality of pistons driven by the rotation of a rotatable shaft. The housing is provided with a mounting member for attaching the compressor to a mounting object outside the compressor. The mounting member is fixed to the wall of the housing adjacent to at least one of the suction chamber and the discharge chamber. An auxiliary chamber that augments at least one of the suction chamber and the discharge chamber is formed by a recess in the wall at the location of the mounting member.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.